AstraZeneca PLC released more pivotal-trial data for its Covid-19 vaccine, saying the shot was 76% effective at preventing Covid-19 with symptoms in a fuller analysis of study results than the company had earlier provided.
AstraZeneca said its latest figures on the vaccine’s efficacy was based on an analysis of 190 cases of symptomatic Covid-19 in the trial, 49 more cases than the company had analyzed earlier.
Despite the additional cases, the vaccine’s performance was in line with what AstraZeneca had first reported.
The London-based drugmaker had drawn fire earlier this week after it had provided preliminary data from the trial indicating its vaccine was 79% effective in 141 subjects.
An independent study-monitoring board said the data were out of date, prompting the U.S. National Institute of Allergy and Infectious Diseases to issue an unusual statement raising the experts’ concerns.
The tempest added to the clouds that have hovered over the shot, which AstraZeneca developed in partnership with the University of Oxford.
Its rollout has been marred by a series of missteps including how the partners communicated earlier U.K. trial results. They presented a confusing array of dosing sizes and schedules, a wide range of efficacy results and few elderly trial subjects.